Iran indicated yesterday it might allow diplomats visiting Tehran for this week's Non-Aligned Movement (NAM) summit to go to the Parchin military base, which UN nuclear experts say may have been used for nuclear-related explosives tests.

When asked about the possibility, Deputy Foreign Minister Mohammad Mehdi Akhoundzadeh said, "Such a visit is not customary in such meetings...However at the discretion of authorities, Iran would be ready for such a visit," the Iranian government-linked news agency Young Journalists Club reported.

The tentative offer was made just three days after the International Atomic Energy Agency (IAEA) again requested access to Parchin for its inspectors at a meeting in Vienna.

Iran is hosting the NAM summit, which ends on Friday, at a time when the West is trying to isolate the Islamic Republic over suspicions it is seeking a nuclear weapons capability. Tehran says its atomic programme has only peaceful aims.

Any visit to Parchin by NAM representatives would do little to calm Western concerns or those of the IAEA whose talks with the Iranians ended on Friday without agreement.

The U.N. body suspects that Iran has conducted explosives tests in a steel chamber at Parchin relevant for the development of nuclear weapons, possibly a decade ago.

Citing satellite pictures, Western diplomats say they believe Iran in recent months has been cleansing the site where the experiments are believed to have taken place of any evidence of illicit nuclear activity.

The IAEA is voicing growing concern that this would hamper its investigation if it ever gained access to Parchin.

Last week diplomatic sources said Iran had covered the building believed to house the explosives chamber with a tent-like structure, fuelling suspicions about a clean-up there.